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  • Author or Editor: Geno Picchioni x
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Floriculture, among the fastest-growing agricultural segments in New Mexico, is creating job opportunities for graduates. Limited faculty resources restrict growth in floriculture academic programs, particularly for curricular modernization, extracurricular activities, and capacity building of the student:industry relationship. Federal funding has provided a Program Coordinator to lead our floriculture academic programs, responsible for raising technical quality of floriculture courses, recruitment and retention of undergraduates, and establishment of regional alliances with industry to exploit job opportunities. During the first year of the program (2003), deliverable products included course modules, fund raising protocols, and public school workshops. Results demonstrate an affinity for students of Hispanic origin to the program (over 40% of enrollments). Industry support included over a 2-fold increase in 2003 horticultural internship placements, financial aid, and donations of expendable materials. Floriculture student participation in intra-campus governance and off-campus community service projects also defrayed program costs and resulted in institutional gain. Over 80% of the 25 students enrolled in the beginning floral design and floral crops judging class agreed or agreed strongly that they had an obligation to engage in fund raising efforts to strengthen the floriculture academic program. Our intent is to build the floriculture teaching program into a template that can be replicated into the future through sustained institutional commitment. The program can serve as a model for other academic departments seeking diversification of horticulture academic programs and recruitment of a diverse student body, but struggling with limited human resources.

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Lupinus havardii (Big Bend bluebonnet) is a winter annual plant indigenous to the semiarid southwestern U.S. with potential to become a new cut flower commodity. Nothing is presently known about the mineral nutrition of bluebonnet in greenhouse conditions, either in the whole plant or its short-lived cut racemes, and its possible relationship with vase life longevity. At first appearance of floral buds, supplemental Ca treatments (0, 2.5, 5.0, and 10.0 mm Ca using CaCl2) were added to the nutrient solution over a 2-month growing period, to evaluate the influence of Ca on plant nutrient allocation patterns, nutrient uptake and utilization, and raceme physiology after cutting. Ca supplementation increased net Ca uptake per plant by 40%, 77%, and 95% over the control (2.5, 5.0, and 10.0 mm Ca, respectively; P < 0.05). The increased Ca uptake per plant increased Ca concentration in racemes (a weak Ca sink), which resulted in marginal increases in vase life duration (1 day). This positive influence on vase life duration was not significant due to limited number of raceme replicates. When plants were supplemented with 5 mm Ca, the net accumulation of Ca, P, K, and Mg in roots increased by 4 to 5 times over the control roots. These increases occurred in parallel to an increase in root dry matter production. Similar patterns were observed in the net accumulation of Ca, P, K, and Mg per plant. In our conditions, Ca supplementation (5 mm) enriched raceme Ca concentration as well as whole-plant consumption of Ca, P, K, and Mg in bluebonnet plants. These data will be useful in developing fertilization strategies for this new and promising greenhouse floral crop.

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Lupinus havardii has gained popularity as a potentially new and unique cut flower species, but its compound, ethylene-sensitive inflorescences (racemes) undergo rapid senescence and deterioration on cutting. The purpose of this study was to evaluate the influence of Ca culture solution applications on L. havardii cut-flower longevity. Four supplemental Ca treatments were incorporated into the nutrient solution (0, 2.5, 5.0, and 10.0 mM Ca using CaCl2), with four replications in a randomized complete-block design. Raceme Ca concentration increased with increasing Ca application, ranging from a low 5300 mg·kg-1 dry weight (0 mM supplemental Ca) to a high of 7500 mg·kg-1 (10.0 mM supplemental Ca). Calcium application deferred the daily loss in raceme fresh weight (FW) for up to 10 days of vase life in a concentration-dependent manner (P < 0.01), with the effect most pronounced between 5 and 9 days following cutting (average FW of 72% and 83% of day zero values for the control and 10.0 mM Ca, respectively, with 2.5 and 5.0 mM treatments intermediate). The cut racemes of L. havardii are model organs for spatially and sequentially organized postharvest development, with continued, 6-day postcutting life including 4-fold increases in cell permeability of basal, most mature flowers, marginal but significant increases in cell permeability of the most recently expanded flowers, and a 50% increase in total flowers number resulting from inflorescence expansion. Preliminary data indicate that manipulation of Ca nutrition may be a viable, inexpensive, and environmentally safe alternative to silver-based compounds currently in use for the vase life extension of L. havardii inflorescences.

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The uptake and distribution of foliar and soil applied boron has been followed in a seven year old pistachio orchard by utilizing 10B isotope dilution techniques and ICP-MS determination. In conjunction with these uptake studies, in-vivo and in-vitro measurements of pollination and fruit set have been used to determine the role of boron in flowering and fruit set.

Foliar applications of boron (1, 2.5 and 5 kg/400 l) resulted in improved fruit set when compared to control trees receiving no supplemental B even when tissue B levels in these control trees appeared adequate (>60 μg/g dwt). Results indicate that B applied to male trees in the late dormant phase (february) is effective in enhancing in-vitro pollen germination by as much as 50%. Movement of B into flower buds and fruit clusters was verified using 10B techniques thus demonstrating the potential usefulness of this technique in correcting incipient B deficiency. A possible role of B in the flowering and fruiting process is discussed.

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Total plant biomass, shoot growth rate, and the periodicity in shoot growth and color of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy `Tifgreen'] in response to slow-release fertilizer N sources, rates, and application frequencies were studied in two, 120-day greenhouse studies. Plugs were planted in plastic cylinders filled with a growing medium of 93 sand: 7 peat moss (w/w). The first experiment was completed under progressively increasing photoperiod (13.1 to 14.9 hours) typical of the long-day requirements for bermudagrass growth. The second experiment occurred under progressively decreasing photoperiod (13.7 to 10.7 hours) representative of autumnal growing conditions and declining growth and N demand. Urea (URE), sulfur-coated urea (SCU), and hydroform (HYD, methylene urea polymers) were broadcast at N rates of 100 or 200 kg·ha-1 and at frequencies of 20 or 40 days. Bermudagrass was clipped at 3-day intervals and the average daily clipping growth rate (increase in shoot dry matter; DM) reached a maximum of 11.5 g·m-2 per day. Use of the least soluble source, HYD, produced the lowest total clipping DM, and at low HYD rate and frequency, leaf color intensity was frequently below the accepted standard of 7, in the scale from 1 “tan” to 9 “dark green”. A greater responsiveness of bermudagrass to N rate and application frequency (increased clipping growth rate and color intensification upon N application) occurred under increasing photoperiodic conditions as compared to decreasing photoperiodic conditions. Both clipping growth and color changed cyclically through time and mainly under long-day photoperiod (>12 hours), with greater oscillation at longer fertilization interval (40 days). With either SCU or URE, at low N rate and frequency (total N application of 0.25 g·m-2 per day), clipping growth rates were above 4 g·m-2 per day, and turf color was at or above the minimum quality standard through most of the growing period. Higher total SCU and URE application rates, previously shown to increase N leaching losses in these experimental conditions, produced significantly more clipping growth and did not appear to intensify color sufficient to warrant the increased risk of N loss.

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A field study was conducted in 1997 and 1998 in Ojinaga, Chihuahua, Mexico, to compare biomass production potential and ion uptake capacity of seven tree species and clones, Eucalyptus camaldulensis (4016, 4019, and 505), hybrid Populus (029, 197, and 367), and seedlings of Robinia pseudoacacia irrigated with saline municipal wastewater. Total dry biomass production was greatest with poplar clone 367 (657 g) and eucalypt clone 4019 (643 g). Both clones also provided the most aboveground biomass (463 and 528 g, respectively), essentially because of their greater stem biomass (274 and 234 g, respectively). Poplar clone 367 had the highest lateral branch biomass (84 g), followed by eucalypt clone 4019 (75 g). The clones with the greatest leaf biomass were eucalypt clone 4019 (179 g), followed by eucalypt clone 505 (148 g) and poplar clone 367 (145 g). In all tree selections, Cl concentration was highest in the leaves with poplar clone 197 having the highest concentration (>2%), but the lowest subsequent winter survival at just 55%. The tree with the second lowest survival rate, poplar clone 029 (76%), also had the second highest Cl concentration in its leaves, almost 1.5% Cl. Eucalypt clones 4019 and 4016 accumulated the most total Cl in its tissues (327 and 236 g per tree, respectively) followed by poplar clone 029 (216 g per tree). Eucalypt clone 4019 accumulated the most Na in its tissues (109 g per tree) followed by poplar clone 367 (74 g per tree). In conclusion, poplar clone 367 and eucalypt clone 4019 seem to be sufficiently salt-tolerant for these saline conditions, having high survival, growth, and biomass capacity and perform well under high biomass-generating, short rotation conditions. Eucalypt clone 4019 is also an effective accumulator of Cl and Na ions and may be the most suitable tree for the remediation of salt-affected land in these experimental conditions.

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Factors affecting the phloem mobility of foliar-applied B have received little study. The purpose of this experiment was to evaluate foliar retention of B solutions, foliar uptake kinetics, and phloem mobility of foliar-applied B among four tree fruit species. Leaves on current-year shoots of nonbearing 'Red Delicious' apple, 'Bartlett' pear, 'French' prune, and 'Bing' cherry were immersed in 1000 mg/liter B solutions (supplied as 10B-enriched boric acid) in midsummer. Export of the applied label from leaves was monitored between 0 and 24 h, and throughout the following 20 days by ICP-mass spectrometry. Uptake by leaves increased steadily in all species between 0 and 24 h, and reached 80% to 95% of the applied quantity within 24 h. By 24 h, 62% to 75% of the applied label, depending on species, had been exported from the treated leaves. Apple leaves retained, absorbed, and exported over twice the amount of labelled B as prune and pear leaves, and nearly four times the amount of cherry leaves. Foliar retention largely controlled the capacity for uptake and export.

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Cucumber (Cucumis sativus L. cv. Fidelio) grown in sand culture in the greenhouse was trickle-irrigated with nutrient solution containing 0, 10, or 50 mm NaCl. Gas exchange of Individual leaves was measured by a portable infrared gas analyzer et saturating photosynthetic photon flux. Salt at 10 mm had no detectable effect on plant performance, but exposure to 50 mm NaCl caused net CO2 fixation to decline by 33% and 48% in the eighth and ninth oldest leaves, respectively. Stomatal conductance and transpiration rate were also reduced (≈ 50%) In these leaves. These differences, as well as lower leaf water potentials, were associated with a 60% reduction in fruit fresh weight. The relationship between net CO2 fixation and intercellular (substomatal) CO2 concentrations was determined for individual, attached leaves of plants with roots exposed to various concentrations of NaCl in hydroponics. With 50 and 100 mm NaCl, a nonstomatal contribution to the inhibition of photosynthesis at the chloroplast level was Indicated by strong inhibition of CO, fixation at a saturating CO2 concentration. Salt-induced inhibition of CO2 fixation was associated with accumulation of Na+ and Cl-, and lower K+ in the individual leaves examined.

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Lipid metabolism in lightly-processed vegetables has received little evaluation. This study monitored changes in phospholipid (PL) concentrations of shredded carrots during a 10-day storage period at 10 C and 95% RH. Following shred preparation on day 0, total tissue PL (molar basis) increased by 15%, 33%, and 47% within 2, 5, and 10 days, respectively. PL classes were then separated using normal phase HPLC, a gradient system of isopropanol:hexane:water, and an evaporative light scattering detector. Together, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) comprised over 75% of total PL, and increased by 23-26% after 10 days (μg/g dry weight basis). However, concentrations of phosphatidic acid (PA), usually regarded as a membrane degradation product, increased nearly 100% by day 10. These data suggest that prolonged storage of carrot shreds may greatly affect rates of net PL synthesis and catabolism.

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